Background:

Oncology biosimilars hold the promise of reducing costs in Japan. Although the adoption of oncology biosimilars have been modest due to physicians’ perceptions and lack of operational guidance that supports usage to biosimilars, Japan showed an increase in the uptake of biosimilars.

Objectives: To understand patient and hospital characteristics, and the pattern of utilization of oncology biosimilars in Japan oncology practice.

Methods: A retrospective analysis of hospital database from January 2019 to September 2021 was performed. Patients aged ≥18 years with at least one claim of bevacizumab-BS-Pfizer, rituximab-BS-Pfizer, or trastuzumab-BS-Pfizer, and at least one claim with the indicated oncology diagnoses approved in Japan were included. Descriptive statistics for patient demographics, diagnoses, and treatment patterns including switching were reported.

Results: Overall, 1961 patients were included in the analyses, with 1293, 519, and 149 having at least one claim for bevacizumab-BS-Pfizer, rituximab-BS-Pfizer, and trastuzumab-BS-Pfizer, respectively. At baseline, 68.4% patients were aged ≥65 years, and 47.9% were female. Among inpatient patients, the mean of Charlson comorbidities index was 4.7. About 45.5% were admitted to hospitals with over 499 beds. The most common indications for bevacizumab-BS-Pfizer were colorectal cancer (90.1%), followed by non-small cell lung cancer (8.4%). Patients on rituximab-BS-Pfizer all had a diagnosis of non-Hodgkin’s lymphoma, and for trastuzumab-BS-Pfizer: breast cancer (85.2%) and gastric cancer (14.1%). Across all indications, 53.1%, 28.0%, and 13.4% of patients switched from the reference drug of bevacizumab, rituximab, and trastuzumab, respectively.

Conclusion: Our results have shown that oncology biosimilars have become well accepted in extrapolated indications. Switching between reference product and biosimilars have been adopted in Japan oncology practice.